Some apps try to do their own DNS, and they look for an /etc/resolv.conf
file. While we're at it, we might as well put in an /etc/hosts too.

With a little work, we can get all this info from /net/ndb. ipconfig +
DHCP will put that info in place. However, static configs didn't have DNS.
Now they do, and it'll get placed in /net/ndb. That's what all the Plan 9
programs will expect.

Thus all static configs in the custom /etc/network/local.d/ files ought to
set a DNS entry for their hosts.

We don't really need the old kern/kfs/etc/network/default either - those
machines are long gone, and if anyone wants to use them, put those in
local.d instead.